The Community Based Participatory Research project will evaluate the relationship between early life asthma and traffic-related air pollution. The research questions have developed from Children's Environmental Health Center research cooperation with the Long Beach Alliance for Children with Asthma and the Center for Community Action and Environmental Justice, two broad based coalitions of organizations representing children with asthma in communities with some of the heaviest traffic in southern California. Preliminary results suggest that exposure to oxidant pollutants near homes may be associated with asthma with onset early in life, but there is considerable uncertainty as to these relationships. We propose to examine this question in a case-control study of asthma persisting to school entry, but with onset earlier in life, in children resident in the same home since before age 2. We also hypothesize that susceptibility to ambient air pollution will vary based on genotype for GSTM1, GSTP1, NQO1, HO-1, and TNF-alpha, genes involved in the biologic response to oxidant air pollutants. Lifetime exposure will be assessed by calibrating home measurements to the extensive historical exposure assessment from a monitor in each community operating continuously during the lifetime of participants. Traffic density in close proximity to homes will be estimated from traffic counts made by the California Department of Transportation. Community participation in study promotion to participants and in data collection and interpretation will enhance both the quality of Center research and of the environmental action plans for families of children with asthma in ongoing projects of the community partners. The novel presentation of results in terms of the burden of disease in two areas encompassing almost 1 million people represented by community research partners promises to increase the level of local awareness of the health impact of air pollution. A steering committee representing university and community research partners, and policy makers, will work closely with the Community Outreach and Translation Core to provide the scientific basis necessary for developing policy for the more widespread protection of children from the effects of air pollution.